He warned that university leaders risked "colluding in the mass consumption" of drugs on campuses by ignoring the issue.

Writing in the Daily Mail, the former head teacher said he believed a "revolution from below" was the way forward.

He said: "The middle way, which we are rolling out atBuckingham, aims to make the taking of illegal drugs as socially unacceptable as cigarette-smoking now is in public.

"We aim to do this not by focusing on expulsion - this can lead to already marginalised students experiencing acute difficulties - but by a compassionate policy of making it clear that drug-taking is totally unwelcome on campus."

Two-fifths of students using drugs

Struggling students will be given support, he added, but those who repeatedly flout the policy will be asked to leave the university.

Ultimately, the university is working towards a "student-framed contract" in which people will promise not to engage in drug-taking, he said.

Earlier this year, a survey by the National Union of Students (NUS) found almost two-fifths (39%) of students were currently using drugs, while 17% had done so in the past.

The organisation argued that universities should support students rather than punish them for drug-related behaviour.